VFD for De Vallière H.130C Lathe

Sorry to clog up this VFD forum with yet more of same questions as many others, but I've searched past posts for answers, THINK I'm on the right track, but am still a little unsure before I pull the trigger and buy a VFD.

The basics:

Lathe, De Vallière H 130C,made in France, circa 1950's.

Motor: 3-phase 2-speed 850/1700 rpm 1.6hp/3hp. I would be operating on 240 VAC single phase.

Motor nameplate data (most in French:

Type D81.60
Current TR 1
Frequency 60
cos. 0.70
Volts 220 Amps 6.8/9.5
RPM 850/1700
Service 141372

What I've concluded so far (if you think differently, please answer):

- Buy quality from a reputable dealer and don't try to save by buying cheap unknown Chinese brands from Amazon

- Chose at least a 3 HP or larger VFD to run a 3 HP motor

- For use with a two-speed motor permanently lock the speed switch on the lathe at the high position and then use the VFD to set the lower speeds.

- Slight worries about upstream spikes or harmonics from a VFD affecting our household electronics/appliances, or those of neighbors on our grid. Have read that adding a load reactor can supposedly minimize, but not eliminate this. Don't know how true this is.

Thanks for your help, and any other views or suggestions.


Richard

Adding a load reactor does absolutely nothing with regard to the line side. It's on the LOAD side. You want a load reactor if the motor is old and was not made for use with a VFD. 1950s motor, guaranteed it was not, so I would invest in at least a load reactor if you want the motor to last a lot longer. Alternatively though (and what a lot of people do) is that since you already own that motor and it's already old and may fail for other reasons anyway, just use it until it does, then spend the money on a better motor instead of a load reactor.

Modern VFDs don't make "spikes" on the line side (unless they blow up); the internet is full of false information in this regard. They do however create harmonics and sometimes that can affect sensitive things like older TVs. If I were you, I would connect it and IF you have some effects show up on your TV, then deal with it. Chances are you will not.

The bigger issue with VFDs that people often ascribe falsely to "harmonics" is that the output wires (going from the VFD to the motor) will act like a relatively powerful FM radio transmitting antenna (FM = Frequency Modulation, which is exactly what a "Variable Frequency Drive" does). So to prevent that from being a problem, you must shield the wires, not from things getting IN, but from the RF getting OUT. That can be STEEL conduit that is properly grounded, or it can be what's called "VFD cable" that has screens inside that you ground at both ends. If you use "portable cord", Romex or loose wires in PVC conduit (or no conduit), you get all sorts of interference with other appliances and systems in your house and your neighbors. I once got tracked down via RF triangulation on a military base from 20+ miles away because I was using a 5HP VFD without having the output shielded (I was authorized to be there, but nobody knew what that RF signal was so they sent MPs with guns!)